Female, because, she's just zelda.
There is no "either/or." XD
She doesn't. She disguises as a male but never actually changes her sex.Yeah, but she "switches" genders..? (Awkward.)
This isn't which she/he is. This thread is about which one you prefer.
You can't prefer one or the other because she is a woman. There is no male Sheik.
I refer to him as male, as the reason Zelda transforms into Sheik is to hide from Ganondorf, and Ganondorf is looking for a female.